基于MEMS技术的SU-8胶被动微阀片的设计与研制

为解决微流体在微流控芯片上的单向流动，进而实现生化反应的片上系统，采用微机电系统（MEMS）技术加工出SU-8胶微型阀片．SU-8胶阀片具有弹性模量和弹性常数低、开启压力小、反向泄漏小、易于加工等特点．从理论上分析了不同厚度（10μm，15μm，20μm，25μm）的微型阀片在不同压力作用下的挠度和应力分布，在相同尺寸和压力下，SU-8微阀片的挠度与传统的硅阀片的挠度相比要大10倍左右．讨论了有阻尼作用下的谐振频率以及过流特性。可知阀臂和阀座的尺寸是影响阀片性能的主要因素．给出了加工工艺，测试了阀片的正反向过流性能，以水作为工作物质，得到3种厚度阀片的过流曲线，其最大正向流速达到7000μL／min．

Design and Development of SU-8 Check Microvalve Based on MEMS Technique

The SU-8 microvalve was fabricated by micro electro mechanical systems （ MEMS ） technique to solve one of stumbling blocks for liquid to flow in one way and lab on chip to miniaturize successfully. There exist some advantages such as low Young modulus and elastic constant, little turn-on pressure, low reverse leakage, fabrication easy and so on. Displacement and stress of microvalve with four thicknesses （10μm, 15μm, 20 μm and 25μm ） were discussed theoretically under different pressures. The displacement of SU-8 microvalve is 10 times greater than that of silicon microvalve with the same structure and pressure. Flow characteristics and resonance frequency were investigated under condition that microvalve work in the air and the damping environments. The performance of microvalve is influenced remarkably by dimension of microvalve＇s structure. Forward and backward flow characteristics were tested by experiment and fabrication processes were presented. The flow curves of three thicknesses of microvalve were achieved under different forward and backward pressure difference when using water as working media, and the maximal forward flow rate reached 7 000μL/min.